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Gannets are colonial breeders on islands and coasts, normally laying one chalky, blue egg. It takes five years for gannets to reach maturity. First-year birds are completely black, and subsequent sub-adult plumages show increasing amounts of white.

The three gannet species are now usually placed in the genus Morus, Abbott's booby in Papasula, and the remaining boobies in Sula. However, some authorities believe that all nine sulid species should be considered congeneric, in Sula. At one time, the various gannet species were considered to be a single species.

Most fossil gannets are from the Late Miocene or Pliocene, a time when the diversity of seabirds in general was much higher than today. It is not completely clear what caused the decline in species at the end of the Pleistocene; increased competition due to the spread of marine mammals may have played a role.

The genus Morus is much better documented in the fossil record than Sula, though the latter is more numerous today. The reasons are not clear; it might be that boobies were better-adapted or simply "lucky" to occur in the right places for dealing with the challenges of the Late Pliocene ecological change, or it could be that many more fossil boobies still await discovery. Notably, gannets are today restricted to temperate oceans while boobies are also found in tropical waters, whereas several of the prehistoric gannet species had a more equatorial distribution than their congeners of today.

In many parts of the United Kingdom, the term "gannet" is used to refer to people who steadily eat vast quantities of food especially at public functions.[1][2] But this characterisation, that implies that the birds feeding behaviour is one of grabbing all the available food, is not borne out by recent studies tracking gannet fishing patterns.[3]

Young gannets were historically used as a food source, a tradition still practised in Ness, Scotland, where they are called "guga". Like examples of continued traditional whale harvesting the modern day hunting of gannet chicks results in great controversies as to whether it should continue to be afforded "exemption from the ordinary protection afforded to sea birds in UK and EU law".[4][5]